The invention relates to a bow tensioning device and more particularly a device that reduces the draw weight of the bow while the bow is being drawn, and permits full thrust after the bow is drawn.
Archery bows and particularly compound bows can be difficult to draw. A compound bow typically has a high initial draw weight and the draw weight is reduced or let-off when the bow is fully drawn. As an example, a compound bow may have an initial draw weight of eighty pounds but may have a fifty percent (50%) let-off at full draw, which reduces the holding force of the drawn bow to about forty pounds.
The high initial draw weight makes it difficult for some archers to draw a compound bow. Also, once the bow is drawn, the force of the bow makes it difficult to relieve the tension on the bow without taking a shot.
A typical compound bow comprises a pair of flexible limbs mounted on opposite sides of a riser positioned between the limbs. The riser serves as the handle of the bow. Each limb is bolted to the riser by a single bolt. The bolts can be tightened or loosened in order to "tune" the compound bow and adjust the tension and draw weight of the bow. A prior art bow construction is shown in FIG. 1. In such a bow, when the bolts are loosened, there is less spring force on the limbs when the bow string is drawn, thus reducing bow tension. This, however, produces a corresponding reduction in bow thrust during operation and thus reduces the performance of the bow. When the bolts are tightened, bow tension increases to its maximum level.